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[Bug tree-optimization/33294] New: [4.2/4.3 Regression] -fno-strict-aliasing -ftree-vrp miscompilation
- From: "belyshev at depni dot sinp dot msu dot ru" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 3 Sep 2007 17:46:11 -0000
- Subject: [Bug tree-optimization/33294] New: [4.2/4.3 Regression] -fno-strict-aliasing -ftree-vrp miscompilation
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
Compile with "-O2 -fno-strict-aliasing", fails on amd64 and alpha at least.
Doesn't fail with -fno-tree-vrp. Seems to be related to bug 32575. Breaks
linux kernel in many places (this asm is used with prefetch instruction).
struct T { void *p; } *t;
int main (void)
{
struct T *a;
a = t;
asm volatile ("" : : "m" (*(unsigned long *) a));
if (a)
__builtin_abort ();
return 0;
}
--
Summary: [4.2/4.3 Regression] -fno-strict-aliasing -ftree-vrp
miscompilation
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: belyshev at depni dot sinp dot msu dot ru
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33294